Wyniki wyszukiwania - BazTech

1

Numerical studies on the influence of air staging on the temperature of flue gas and emission of gases in the combustion chamber of OP 230 boiler

Hernik B., Jagodzińska K., Matuszek D.

Chemical and Process Engineering

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2018

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Vol. 39, nr 1

59–-74

EN

The primary methods of reducing nitrogen oxides, despite the development of more advanced technologies, will continue to be the basis for NOx reduction. This paper presents the results of multivariate numerical studies on the impact of air staging on the flue gas temperature and composition, as well as on NOx emissions in a OP 230 boiler furnace. A numerical model of the furnace and the platen superheater was validated based on measurements using a 0-dimensional model of the boiler. Numerical simulations were performed using the ANSYS Workbench package. It is shown that changes in the distribution of air to OFA nozzles, the angle of the air outflow from the nozzles and the nozzle location involve a change in the flue gas temperature and in the volume of NOx and CO emissions at the furnace outlet.

2

An analysis of coal and coal mine methane co-combustion in an 140 t/h pulverized coal boiler

Jagodzińska K., Hernik B., Pronobis M.

Transactions of the Institute of Fluid-Flow Machinery

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2017

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nr 137

3--18

EN

The paper presents an attempt to evaluate the impact of coal and coal mine methane cocombustion on the physics of the heat exchange in an 140 t/h pulverized-coal boiler through an analysis of 21 combinations of the boiler operating parameters – three diﬀerent boiler loads (50, 75, and 100%) and seven values of the ﬁred gas thermal contribution (0–60%). The obtained results are the temperature distribution of ﬂue gas and steam in the boiler characteristic points, the heat transfer coeﬃcient values for the boiler individual elements expressing the nature of changes in the heat transfer and the change in the boiler eﬃciency depending on how much gas is actually ﬁred. An increase in the amount of co-ﬁred gas involves a temperature increase along the ﬂue gas path. This is the eﬀect of the reduction in the amount of heat collected by the evaporator in the furnace. For these reason, the ﬂue gas temperature at the furnace outlet rises by 9 K on average per a 0.1 increment in the ﬁred gas thermal contribution. The temperature rise improves the heat transfer in the boiler heat exchangers – for the ﬁrst- and the secondstage superheater the improvement totals 2.8% at a 10 pp. increase in the ﬁred gas thermal contribution. However, the rise in the ﬂue gas temperature at the boiler outlet involves a drop in the boiler eﬃciency (by 0.13 pp. for a rise in the ﬁred gas thermal contribution by 0.1).

3

The impact of changes in the configuration of burners and OFA nozzles on the parameters of the OP-380 boiler furnace chamber

Hernik B.

Archivum Combustionis

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2015

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Vol. 35 nr 2

131--145

EN

The paper presents the results of numerical investigations of the impact of changes in the configuration of burners and OFA nozzles on the flue gas temperature and the content of oxygen and NOx at the OP-380 boiler furnace chamber outlet. The analysis is based on air staging – one of the primary methods of reducing NOx emissions. Five variants of changes in the configuration of burners and OFA nozzles are considered. The obtained results indicate that a proper configuration of burners and OFA nozzles leads to a reduction in NOx emissions and has a strong influence on the flue gas temperature and oxygen concentration in flue gases in the furnace chamber.

4

Numerical calculations of WR-40 boiler based on its zero-dimensional model

Hernik B.

Chemical and Process Engineering

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2014

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Vol. 35, nr 2

173--180

EN

Generally, the temperature of flue gases at the furnace outlet is not measured. Therefore, a special computation procedure is needed to determine it. This paper presents a method for coordination of the numerical model of a pulverised fuel boiler furnace chamber with the measuring data in a situation when CFD calculations are made in regard to the furnace only. This paper recommends the use of the classical 0-dimensional balance model of a boiler, based on the use of measuring data. The average temperature of flue gases at the furnace outlet t”k obtained using the model may be considered as highly reliable. The numerical model has to show the same value of t”k. This paper presents calculations for WR-40 boiler. The CFD model was matched to the 0-dimensional t”k value by means of a selection of the furnace wall emissivity. As a result of CFD modelling, the flue gas temperature and the concentration of CO, CO2, O2 and NOx were obtained at the furnace chamber outlet. The results of numerical modelling of boiler combustion based on volumetric reactions and using the Finite Rate/Eddy-Dissipation Model are presented.

5

Developing a CFD model of a 60kWt fixed-bed gasifier (GazEla)

Sobolewski A., Węcel D., Hernik B., Kotowicz J.

Archivum Combustionis

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2013

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Vol. 33 nr 2

67--78

EN

Using biomass for thermal and electric power generation is now one of the possibilities of reducing CO2 emissions. In many cases, this requires an application of a biomass gasification installation. Because biomass properties can vary to a great extent, the existing gas generators need continuous upgrading. The research in this area should comprise both on-site testing carried out at real facilities and numerical modelling. The results of the works will make it possible to construct a gasifier featuring an appropriate structure and contribute to a better understanding of the gasification processes occurring in the biomass bed. This paper presents an attempt to develop an appropriate mathematical model for an existing low-capacity fixed-bed gasifier. Alder chips made up the biomass to be analyzed and air was the gasifying medium. An innovative biomass gasifier called GazEla, with the nominal thermal power output of 60 kWt, was selected for the purposes of numerical modelling. The main object of the analysis was to build a three-dimensional model of the gasifier and to obtain the outlet gas composition similar to experimental data. The porous body model served as the model of the biomass fixed bed and char. Selected chemical reactions reflected typical combustion and gasification processes occurring in fixedbed gasifiers.

6

A CFD model of the fluidized-bed furnace chamber of the OP-150 boiler pregasifier

Hernik B.

Archivum Combustionis

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2013

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Vol. 33 nr 2

79--96

EN

The values obtained by means of measurements of the fluidized-bed furnace chamber of the pregasifier of the Stalowa Wola power plant OP-150 boiler were compared with the results of numerical calculations performed using the Ansys.Fluent code [1] to verify the numerical model (and to select the sub-models). Two variants of the CFD model were taken into consideration in an attempt to simulate the furnace chamber operation in real conditions and in conditions created by closing the “circulation windows”. The steady-state processes of biomass pyrolysis, of the combustion of the volatile matter resulting from it and of the gasification and combustion of char were modelled. Some simplifications (solid bed, single-phase flow model in the Euler coordination system) were assumed in the CFD model, which did not have a considerable adverse effect on the obtained results.

7

Numerical modeling of BP 1150 boiler by commercial numerical code

Hernik B.

Journal of Power Technologies

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2012

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Vol. 92, nr 1

34-47

EN

In this paper a numerical model was created for the combustion chamber of BP 1150 boilers of Opole Power Plant with an additional set of protection air system nozzles. The calculation was using Ansys Fluent CFD. Three cases of air distribution to OFA and SOFA nozzles were modeled. The ratio of air was increased to OFA and SOFA nozzles by taking secondary air from burners to decrease NOx emission. The distribution of primary and secondary air was done so that the ratio of air from the protection air system was at a stable 10% of secondary air. A numerical simulation of the furnace of BP 1150 boilers confirmed that staggered air decreases NOx emission and showed the NOx concentrations at various levels of the combustion chamber.

8

A zero-dimensional model used as a basis for numerical modelling of OP-650 boiler

Hernik B., Pronobis M.

Archiwum Energetyki

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2012

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T. 42, nr 2

17--26

EN

The numerical modelling of power boiler furnaces is often performed in the engineering practice. Quite often, however, the balance calculations of the entire boiler are not carried out. In this case, the flue gas temperature at the furnace outlet results from the numerical model and depends on the adopted assumptions (e.g. wall fouling or emissivity). However, the value determined in this way may be wrong, and the presented calculation method makes it impossible to verify it. One of the ways to improve the numerical model accuracy is the verification of the flue gas temperature at the furnace outlet value by calculations fully balanced by a zero-dimensional (0D) model based on measuring data. The numerical calculations should be carried in such a way that the average temperature at the furnace outlet in the computational fluid dynamical (CFD) model equals the temperature obtained from the 0D model. At the same time, the matching of this temperature should result from carefully selected assumptions of the numerical model, which have to correspond to the actual phenomena occurring in the furnace. This model presents the verification of the CFD model for the OP-650 boiler of a 225 MWel power unit. The results of numerical modelling of boiler according to non-premixed combustion model with mixture fraction/PDF (probability density function) approach was presented. Also numerical modelling of boiler with species transport model with volumetric reactions and finite rate chemistry was done.

PL

W praktyce inżynierskiej często wykonywane jest numeryczne modelowanie palenisk kotłów energetycznych, przy czym często nie prowadzi się obliczeń bilansowych całego kotła. Temperatura spalin na wylocie z paleniska wynika wówczas z modelu numerycznego i zależy od przyjętych założeń (np. zanieczyszczenie ścian lub ich emisyjność). Tak wyznaczona wartość temperatury może jednak być błędna, a opisany sposób liczenia uniemożliwia jej weryfikację. Sposobem na poprawę dokładności modelu numerycznego jest weryfikacja temperatury spalin na wylocie z paleniska za pomocą w pełni zbilansowanych obliczeń modelem 0-wymiarowym opartym na danych pomiarowych. Obliczenia numeryczne powinny być tak prowadzone, aby średnia temperatura na wylocie z komory paleniskowej kotła w modelu CFD była równa temperaturze uzyskanej z modelu zerowymiarowego. Jednocześnie dopasowanie tej temperatury powinno wynikać z odpowiednio dobranych założeń modelu numerycznego, które muszą odpowiadać realnemu przebiegowi zjawisk zachodzących w palenisku. W niniejszej pracy dokonano opisanej weryfikacji modelu CFD dla kotła OP 650 do bloku 225 MWel. Przedstawiono wyniki modelowania numerycznego kotła wg algorytmu mixture fraction/PDF - z wykorzystaniem modelu spalania non-premixed oraz wyniki dla modelu opartego na reakcjach objętościowych z wykorzystaniem modelu finite-rate/eddy-dissipation.

9

Kinetics of low nox corrosion of waterwalls in utility boilers

Pronobis M., Hernik B., Wejkowski R.

Rynek Energii

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2010

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nr 6

121-128

EN

High temperature corrosion is currently one of the main causes of failures in utility boilers. In particular, in recent years, low NOx corrosion of waterwalls in the area of the burner belt has caused a significant decrease in the lifetime of tubes. Before the introduction of low NOx combustion methods, the lifetime of waterwalls exceeded 10 or more years, while now it does not exceed 5 - 6 years. The fireside waterwall wear is commonly linked with a lack of oxygen and a high CO concentration in the flue gas accompanied with the presence of sulfur and chlorine compounds. Such conditions are inevitable while using primary NOx reduction methods in coal-fired boilers. The amount of chlorine in the coals used in Polish power plant boilers is rather low (commonly Clr <0,2 %) and therefore the predominant corrosion mechanism is the attack of gas phase H2S, a product of reactions in ash deposits containing sulfur compounds. The paper presents a new equation for calculating low-NOx corrosion rate as well as an exemplary calculation presented as the isolines of tube thickness loss [nm/h] over the rear waterwall in the boiler of the ERSA power plant.

PL

Korozja wysokotemperaturowa jest obecnie jedną z głównych przyczyn awarii w kotłach energetycznych. W szczególności w ostatnich latach niskoemisyjna korozja ekranów komory paleniskowej kotła w obszarze pasa palnikowego znacząco wpłynęła na obniżenie okresu eksploatacji rur. Przed wprowadzeniem nisko-emisyjnych metod spalania okres eksploatacji rur ekranowych przekraczał 10 lub więcej lat, podczas gdy po zastosowaniu niskoemisyjnego spalania nie przekracza 5 - 6 lat. Uszkodzenie ekranów jest zwykle powiązane z brakiem tlenu oraz zwiększoną koncentracją tlenku węgla w spalinach przy obecności związków siarki oraz chloru. Takie warunki pracy ekranów są nieuniknione przy stosowaniu pierwotnych metod redukcji tlenków azotu w kotłach pyłowych. Zawartość chloru w węglu stosowanym w polskich kotłach energetycznych jest raczej niska (zwykle Clr <0,2 %) dlatego korozja powstaje głównie przy obecności gazowej fazy H2S, która jest produktem reakcji w osadach popiołowych zawierających związki siarki. Praca zawiera analizę badań procesów korozyjnych związanych ze spalaniem przy niskiej emisji NOx oraz przykładowe obliczenia rozkładu ubytków rur tylnego ekranu komory paleniskowej kotła OP 650. Obliczenia przeprowadzono w oparciu o własne korelacje opracowane na podstawie badań w skali laboratoryjnej i w pełnej skali przemysłowej.

10

Heat transfer in combined longitudinally finned and plain tube banks

Pronobis M., Ciukaj S., Hernik B., Wejkowski R.

Chemical and Process Engineering

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2009

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Vol. 30, z. 3

485-494

EN

The search for new types of boiler convection surfaces has spurred the creation of arrangements built from plain and longitudinally finned tubes (diagonal and triple-finned tubes). A new geometry of such heat exchanger required the development of a new method for heat transfer calculations. The prezent work is devoted to this topic.

PL

Poszukiwanie nowych rodzajów powierzchni konwekcyjnych doprowadziło do stworzenia układów kombinowanych zbudowanych z rur gładkich i ożebrowanych wzdłużnie (diagonalnych i trójżebrowych). Nowa postać geometryczna wymiennika wymaga opracowania właściwego sposobu obliczania strumienia przejmowanego ciepła. Zagadnieniu temu poświęcono prezentowaną pracę.

11

Badania erozji popiołowej kotłowych pęczków z ożebrowaniem wzdłużnym

Wejkowski R., Pronobis M., Hernik B.

Archiwum Energetyki

|

2008

|

T. 38, nr 1

219-238

PL

Opracowanie zawiera wstępne wyniki badań modelowych erozji popiołowej w pęczkach rur gładkich i ożebrowanych wzdłużnie. Celem badań było określenie wpływu ożebrowania na odporność rur w kotłowych pęczkach konwekcyjnych na zjawisko erozji popiołowej. Badano układy rur gładkich, rur opłetwowanych z żebrami ustawionymi wzdłuż kierunku przepływu czynnika omywającego oraz układy złożone z rur gładkich i opłetwowanych, w których żebra ustawione są pod kątem do kierunku czynnika (tzw. rury diagonalne).

EN

The paper presents the preliminary results of model investigations of fly ash erosion in plain and longitudinally finned banks of tubes. The investigations have been carried out in order to determine the influence of finned tubes application in convective surfaces of boilers on the durability (erosion wear rate). The bundles of plain tubes and of tubes with fins oriented parallel to the flow direction as well as systems of plain and finned tubes with diagonally oriented fins have been investigated.

12

Modelowanie numeryczne układów powietrza osłonowego w kotle OP 650

Hernik B., Pronobis M., Wejkowski R.

Prace Naukowe Politechniki Warszawskiej. Konferencje

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2007

|

T. 1, z. 25

193-201

PL

W artykule przedstawiono wyniki symulacji numerycznej systemu powietrza osłonowego komory paleniskowej kotła OP 650 K5 EI. Rybnik SA (ERSA) przy użyciu oprogramowania CFD Code_Saturne. Przeprowadzono symulacje procesów zachodzących w komorze paleniskowej kotła przy wyłączonym i pracującym układzie powietrza osłonowego (UPO). Zamodelowano także nowy układ o zwiększonej w stosunku do stanu istniejącego liczbie dysz powietrza osłonowego.

EN

The paper presents the results of numerical simulations, in CFD Code_Saturne, of protection air system in front wall fired boiler OP650 K5 in Rybnik Power Plant. Simulations of the furnace process with and without protection air system were done. New concept of protection air system with bigger number of air inlets was also modelled.

13

Simulations of Protection Air System in Front Wall Fired Boiler OP650 in Rybnik Power Plant

Dal-Secco S., Hernik B., Pronobis M., Wejkowski R.

Archivum Combustionis

|

2007

|

Vol. 27 nr 1-2

9-18

EN

The paper presents the results of numerical simulations in Computational Fluid Dynamics Code Code_SaturneŽ of existing protection air system in front wall fired boiler KS type OP6S0 in Rybnik Power Plant (ERSA). Simulations without existing protection air system (WPAS), with existing protection air system (EPAS), with simple modification of existing protection air system (MEPAS) by changing the direction of protection air nozzles, and with more expensive modification by adding new air nozzles (NEPAS) were done. The influence of the swirl in OFA ports on the flue gas composition near the walls was determined. The paper presents also the dependence between the primary, secondary and tertiary air swirls directions in the bumers and the flame symmetry in the fumace.

14

Ocena opłacalności zastosowania przegrzewacza konwekcyjnego z rur ożebrowanych

Hernik B., Pronobis M., Wojnar W.

Energetyka

|

2006

|

nr 4

241-244

PL

Powierzchnie przegrzewaczy są zdeterminowane przez wymagany zakres przegrzewu, stąd ich ożebrowanie prowadzi do zmniejszenia długości rur. Zastąpienie konwencjonalnego I st. przegrzewacza układem ożebrowanym daje w warunkach kotła OP 140 zarówno oszczędność kosztów inwestycyjnych jak i zmniejszenie kosztów eksploatacji pomp wody zasilającej. Dlatego przy planowej wymianie powierzchni tego rodzaju należy wziąć pod uwagę możliwość zastosowania pęczka rur ożebrowanych. Zaproponowany układ rur opłetwowanych charakteryzuje się odpowiednimi właściwościami wytrzymałościowymi.

EN

Superheater surface depends on a needed superheating range hence its ribbing causes shortening of tubes length. Replacing a conventional single-stage superheater with a ribbed system lets you - in case of OP140 boiler - save part of the investment costs as well as lower exploitation costs of feed water pumps. That is why one should take into account the possibility of applying a bank of ribbed tubes as a re-equipment to a conventional superheater during the planned replacement. The proposed finned tubes system has also an adequate strength characteristic.

15

Projektowanie zespołów głównych samolotów bezzałogowych w systemie UNIGRAPHICS

Hernik B., Gadomski J., Frydrychewicz A., Goraj Z.

Zeszyty Naukowe Politechniki Świętokrzyskiej. Mechanika

|

2004

|

Z. 80

205-210

PL

W artykule przedstawiono wybrane zagadnienia związane z zastosowaniem systemu UNIGRAPHICS do projektowania powierzchni bryły płatowca oraz modelowania bryłowego zespołów i podzespołów. Przedstawiono sposób opisu brył, wykorzystanie modułu złożeń oraz zasady modyfikacji. Opisano także możliwość wykorzystania wygenerowanej geometrii przez inne programy obliczeniowe.

EN

This paper presents a design procedure undertaken during development of unmanned aerial vehicles PW-103 & PW-114 at Warsaw University of Technology using UNIGRAPHICS by the research team headed by Prof. Zdobyslaw Goraj within the V FR of European Union in the CAPECON programme. UNIGRAPHICS enables the modeling of separate subsystems and a simple verification if these subsystems fit one the other when integrated. Output data is compatible with an input data needed for an advanced aerodynamic software, for example with the VSAERO input data.

16

Analiza i optymalizacja struktury samolotów bezzałogowych

Gadomski J., Goraj Z., Hernik B.

Zeszyty Naukowe Politechniki Świętokrzyskiej. Mechanika

|

2004

|

Z. 80

143-148

PL

Opracowanie przedstawia metody projektowania i obliczania numerycznego wykorzystane podczas konstruowania struktury nośnej samolotów bezzałogowych PW-103 MALE i PW-114 HALE opracowanych przez zespół kierowany przez prof. dr hab. inż. Zdobysława Goraja z Wydziału MEiL Politechniki Warszawskiej.

EN

This paper presents a design effort undertaken during development of a load structure of unmanned aerial vehicles PW-103 & PW-114 at Warsaw University of Technology by the research team headed by Prof. Zdobyslaw Goraj within the V FR of European Union in the CAPECON Project - No GRD1-2001-4016.

17

Zapobieganie korozji niskotlenowej w różnych układach spalania niskoemisyjnego

Pronobis M., Kalisz S., Ostrowski P., Hernik B., Wejkowski R., Kosałka J., Wrona J., Gruszka S., Heród A., Boryczko G.

Energetyka

|

2004

|

nr 11

726-730

PL

Podstawowe bloki pracujące w PKESA są wyposażone w kotły OP 650 i OP 380. Po wejściu w życie nowych, ostrzejszych norm emisji tlenków azotu, poszczególne elektrownie wprowadzały różne systemy niskoemisyjnego spalania. Podano je w odniesieniu do elektrowni: Jaworzno III, Łagisza, Łaziska i Siersza. Ochronę antykorozyjną opartą na doprowadzeniu powietrza w pobliże ekranów zastosowano w elektrowniach: Jaworzno III, Siersza i Łagisza. Podano różnice między zastosowanymi systemami. Przykładem zastosowania zmiany rozkładu strumieni pyłu węglowego wyprowadzanego z młynów jest modernizacja instalacji młynowo-paleniskowej kotłów OP 650 El. Jaworzno III.

EN

In PKE SA the power units are equipped with OP 650 and OP 380 boilers. Since new and stronger standards of NOx emission were in force, particular power stations introduced various systems of low emission combustion. They are given with regard to following power stations: Jaworzno III, Lagisza, Laziska and Siersza. An anti-corrosion protection based on introducing the air near the waterwall is used in Jaworzno III, Siersza and Lagisza power stations. Given are differences between used systems. As an example of the distribution change of the stream of the coal dust going out from coal mills is presented the modernisation of the milling and combustion system of the OP 650 boilers in the Jaworzno III power station.

18

High altitude long endurance unmanned aerial vehicle of a new generation - a design challenge for a low cost, reliable and high performance aircraft

Goraj Z., Frydrychewicz A., Świtkiewicz R., Hernik B., Gadomski J., Goetzendorf-Grabowski T., Figat M., Suchodolski S.

Bulletin of the Polish Academy of Sciences. Technical Sciences

|

2004

|

Vol. 52, nr 3

173-194

EN

This paper describes a design process of HALE PW-114 sensor-craft, developed for high altitude (20 km) long endurance (40 h) surveillance missions. Designed as a blended wing (BW) configuration, to be made of metal and composite materials. Wing control surfaces provide longitudinal balance. Fin in the rear fuselage section together with wingtips provide directional stability. Airplane is equipped with retractable landing gear with controlled front leg that allows operations from conventional airfields. According to the initial requirements it is twin engine configuration, typical payload consists of electro-optical/infra-red FLIR, big SAR (synthetic aperture radar) and SATCOM antenna required for the longest range. Tailless architecture was based on both Horten and Northrop design experience. Global Hawk was considered as a reference point - it was assumed that BW design has to possess efficiency, relative payload and other characteristics at least the same or even better than that of Global Hawk. FLIR, SAR and SATCOM containers were optimised for best visibility. All payload systems are put into separate modular containers of easy access and quickly to exchange, so this architecture can be consider as a "modular". An optimisation process started immediately when the so-called "zero configuration", called PW-l11 was ready. It was designed in the canard configuration. A canard was abandoned in HALE PW-113. Instead, new, larger outer wing was designed with smaller taper ratio. New configuration analysis revealed satisfactory longitudinal stability. Calculations suggested better lateral qualities for negative dihedral. These modifications, leading to aerodynamic improvement, gave HALE PW-114 as a result. The design process was an interdisciplinary approach, and included a selection of thick laminar wing section, aerodynamic optimisation of swept wing, stability analysis, weight balance, structural and flutter analysis, many on-board redundant systems, reliability and maintability analysis, safety improvement, cost and performance optimisation. Presented paper focuses mainly on aerodynamics, wing design, longitudinal control and safety issues. This activity is supported by European Union within V FR, in the area Aeronautics and Space.